The present invention relates to data storage systems, and more specifically, this invention relates to implementing variable scoping capability for physical tape layout diagnostic structures of tape storage devices.
Many tape storage devices, such as an IBM® 3592/TS1150 storage tape drive, contain an internal data log for mapping measurable characteristics of the tape drive while in operation. This data log is often stored in buffer memory for retrieval and analysis. In some systems, the data log (sometimes referred to as a tape map) stores errors, significant events, operating ranges, and performance statistics for the core functional areas of the tape drive for the duration of a cartridge mount. This complex data structure is a component of a microcode dump file which is used for failure analysis by both engineering and general product support. The tape map content varies according to many factors, such as manufacturer, model, product generation, etc., but is basically a representation of a fixed set of metrics applied to the interaction between media, recording head, servo control, dataflow electronics, and microcode for a given cartridge mount.
This tape map provides a physical view of a mounted cartridge. As the drive is processing data on a given cartridge, the errors, significant events, operating ranges, and performance statistics are stored in the tape map according to their physical location within the cartridge. Physical location is defined by a physical wrap number and a fixed number of equal length sections (or regions) along that wrap extending from beginning of tape (BOT) to end of tape (EOT). Since the region count is fixed for a given tape drive, cartridges of different lengths will have different region lengths, so each cartridge type has a different resolution of data. In general, this resolution does not prevent effective evaluation of tape map data.